Dimensions, tolerances and assemblies - Coggle Diagram
Dimensions, tolerances and assemblies
allowed to vary in only one direction
the upper and lower limits of the dimension are specified
allowed to vary in two directions from the specified dimension.
Upper tolerance - lower tolerance
consists of several dimensions originating from a common reference surface
simplifies parallel dimensions in order to reduce the space used on a drawing
only be used if function of the object would not be affected by the accumulation of the tolerances
Chain + parallel
Dimensioning Small Features
arrow heads can be placed outside the extension line
Dimensioning of Multiple Features
(Number) x dimensions
Radius -> R
Circle, Arc and hole
Circle: dimensioned by diameter
arc: dimensioned by radius.
hole: dimensioned by centrelines
marked with curved dimension lines
Clearance and interference fit
Allowance for two parts to move
it would be difficult to move (or remove) the two interfacing parts. Usually, a lot of force is needed to remove the two parts. Examples are shafts that are fitted through bearings, so that the shaft does not slip.
Types of joints in fusion 360
single translational degree of freedom. It is used for components that slide along one another.
provides two degrees of freedom: one translational and one rotational
fixes two components to one another. It provides no degrees of freedom.
single rotational degree of freedom
allows two degrees of freedom, but components can rotate around different axes
allows three degrees of freedom. It allows two directions of translation in a plane and a single rotational direction normal to that plane
two degrees of rotational freedom: pitch and yaw. Pitch allows components to rotate around the Z axis. Yaw rotates components around the X axis.